1. Field of the Invention
The present invention relates to a lens barrier mechanism incorporated in a lens barrel.
2. Description of the Related Art
Lens barrels (photographic lenses) of compact cameras are generally provided with a lens barrier mechanism for shutting the front of a photographing optical system in an accommodated state (retracted state) of the lens barrel when no pictures are taken. As described in Unexamined Japanese Patent Publication 2000-292670, a mechanism for controlling opening/shutting operations of a set of barrier blades (e.g., sector blades) of such a lens barrier mechanism via a cam ring used for driving lens groups is known in the art.
In this type of lens barrier mechanism, the barrier blades are shut by a spring biasing force and the barrier blades are opened by applying a force against the spring biasing force. Accordingly, in a lens barrel accommodated state, it is conventionally the case that any movable member such as a cam ring is prevented from entering into an operating plane in which the set of barrier blades opens and shuts to prevent the set of barrier blades from interfering with other members. However, to achieve a reduction in length of the lens barrel, the lens barrier mechanism has also been required to achieve a further improvement in efficiency of space utilization.